N.H. Rev. Stat. Ann. § 261-B:1

The department of safety shall issue multi-use decal plates. The design shall provide an area 3 inches by 3 inches for the placement of a decal representing an organization authorized by statute to issue decals or a decal issued by a city or town fire chief to a firefighter or retired firefighter. Except as otherwise provided in this chapter, multi-use decal plates shall have the same effect and be issued in the same manner as other number plates. Multi-use number plates shall retain the "live free or die" logo.